Jersey fits great and has excellent venting breathing. Normally I wear a size small, ordered the SM size and it fits like a fitted small, might be too tight for a true medium. Collar is a bit snug, but just right for a thin guy like myself, those with thicker necks may find it uncomfortable when fully zipped. Sleeves felt a tiny bit longer than normal race fit jerseys but hardly noticeable. Sleeve material is solid (as opposed to meshperforated) but heat didn't seem to be a factor.
Overall I would buy again, if discounted because the actual MSRP is way out of my league.
Great road cycling jersey. Aero fit, stretchy fabric, comfortable in riding position.
Really comfortable and fits great.